Rockbox's USB Stack Performance

Rockbox's USB Stack Performance

Since the early part of February 2008, there has been working USB Mass Storage code available which works with Rockbox targets based on the PortalPlayer SOC. This page endeavours to list performance figures for this new code, and where appropriate, compare it to the performance of the existing USB implementation of the original firmware of the device in question. The test is run using a variation of the below command from a GNU/Linux based host computer :

time dd if=/dev/sdb1 of=/dev/null bs=32k count=1000

This will copy around 32MB from the device to the host and time the process.

In the below tables, there is a column included for the iPod's emergency disk mode. No other target has this, so if you're logging stats for a Sansa, or an H10 - just put an N/A there.

If possible, please also provide results from the test_disk plugin (enable it in apps/plugins/SOURCES first), preferably the 4k and 1M read and write results

Read Tests

Read Tests

Device Name

Time taken by RB USB

Time taken by Emergency Disk Mode

Time taken by OF

Apple iPod G5.5 30GB

33 MB copied, 36.3426 seconds, 902 kB/s

33 MB copied, 6.96309 seconds, 4.7 MB/s

33 MB copied, 5.04788 seconds, 6.5 MB/s

Apple iPod G5.5 80GB

33 MB copied, 7.13356 seconds, 4.6 MB/s

33 MB copied, 5.59582 seconds, 5.9 MB/s

33 MB copied, 2.10249 seconds, 15.6 MB/s

Apple iPod G4 Color 20GB

33 MB copied, 37.7545 seconds, 868 kB/s

33 MB copied, 2.77807 seconds, 11.8 MB/s

33 MB copied, 4.77862 seconds, 6.9 MB/s

Sansa e280

33 MB copied, 31.8638 seconds, 1.0 MB/s

N/A

33 MB copied, 6.49272 seconds, 5.0 MB/s

Write tests

All the below write tests were carried out using the "Full speed" code in svn, since the "High speed" code is still unstable.

Write Tests without file system

For writing tests, I've chosen a smaller file (Exactly 2,000 KBs). This is written to a blank portion of the firmware partition on an iPod to avoid file system overheads.